With native integer backend, `space_leak_001` allocates +40% and regresses in max memory by 100% when compared to gmp
https://gitlab.haskell.org/ghc/ghc/-/jobs/712564
We didn't notice until now since this configuration has been untested in CI for a while. This is due to a bug overwriting the BIGNUM_BACKEND
variable in CI, which will be fixed by !5594 (closed)